Instrumentation is a technique in which instructions are added to a program to collect information when the program runs. Typically, the information collected relates to performance or other behavioral characteristics of the program. A program can be instrumented manually (meaning that the instructions are added, usually to the source code, by a person). A program can be instrumented automatically, by another program (e.g., by a compiler, etc.). Instrumentation can be added to the source code, to byte code or to a compiled binary. Code can be instrumented as the source code is developed. Code can be instrumented right before execution (runtime instrumentation).